Articles on forages, animals, and grazing systems
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Extension Forage Specialist
University of Kentucky
Phone: (859) 257-3358
Fax: (859) 323-1952
The Western KY network held the Western Kentucky Dairy Pasture Walk on June 14, 2013 in Pembroke, KY at Amos Fisher’s Dairy Farm. Dr. Ray Smith, forage Extension specialist, and Dr. Donna Amaral-Phillips, dairy Extension specialist, led discussion along with Amos and helped to answer questions. Topics included dwarf-type forage sorghum for silage, identifying pasture grasses, tall fescue, heat effects on dairy cattle, strip grazing, estimating pasture yield, alfalfa management, and more.
The morning began with a brief introduction to the farm, followed by a farm tour. Amos owns a 70 acre organic dairy operation with a 40 cow herd of Jerseys. He also grows alfalfa, corn to be harvested for grain, and forage sorghum for silage. He manages a rotational grazing system and exercises strip grazing for all his fields.
One of the first topics discussed during the farm tour was dwarf-type forage sorghum. Dwarf-type forage sorghum grows to about six feet tall as opposed to fifteen to twenty feet tall for a regular sorghum plant. However, the dwarf-type is just as leafy, but has shorter internodes (space between the nodes), making the plant leafier per amount of stem. This makes the plant more digestible. Amos and other producers present were interested in Brown Mid-Rib, or BMR, varieties of dwarf forage sorghum. BMR varieties have decreased lignin, which also contributes to increased digestibility. Forage sorghum for silage is sometimes used by farmers instead of corn because it is drought tolerant and has a lower nitrogen requirement than corn.
Grass identification was then discussed, specifically telling the difference between annual ryegrass and tall fescue. Milk production decreases with consumption of KY 31 tall fescue, so emphasis was placed on planting a novel or endophyte free tall fescue for pastures or hay. As with all livestock, tall fescue toxicity issues seem to increase during the summer months. Heat stress can begin in dairy cattle at a temperature-humidity index of 68 degrees Fahrenheit making it extremely important to incorporate shade and water in all pastures. The ergot alkaloids produced by endophyte infected tall fescue can cause vasoconstriction making it even more difficult for cattle to dissipate heat.
Amos also discussed his pasture management plan for strip grazing and the impacts it’s made on both his forages and animals. Dr. Donna Amaral-Phillips discussed the nutritional aspects of managing dairy cattle during the hot summer months, as well as the importance of alfalfa in a dairy grazing system. For more information on grazing dairy cattle, please refer to the article “Pasture for Dairy Cattle: Challenges and Opportunities,” located on the UK Forages website at http://www2.ca.uky.edu/agc/pubs/asc/asc151/asc151.pdf.